Device for Supplying Ink to a Printing Press

ABSTRACT

A device for supplying ink to a printing press, includes a piston pump and a hydraulic or pneumatic cylinder driving mechanism which drives the piston rod of the piston pump and the cylinder driving mechanism includes several cylinder chambers, which are separated from one another and each of which contains a driving piston, which can be acted upon with pressure.

The present invention relates to a device for supplying ink to aprinting press in accordance with the introductory portion of claim 1.

Printing machines, for example, for offset printing, are usuallysupplied with ink by equipment, which comprises an ink pump and anappropriate driving mechanism for the public. Usually, piston pumps, thepiston rod of which is driven by a hydraulic or pneumatic cylinder, areused in this connection.

As the operating speed and efficiency of modern printing pressesincrease, their ink consumption and, with that, the volume pumped by theink pump also increase. Furthermore, in those cases, in which the inkbarrels are far removed from the printing press, it may be necessary tobuild up a high pumping pressure. For this reason, there is a need forcylinder driving mechanisms, which are in a position to employ a veryhigh driving force.

One possibility for achieving this objective consists of scaling thedriving cylinder correspondingly, that is, of increasing the capacity ofits cylinder chambers. However, this entails various disadvantages. Theexternal dimensions of the driving cylinder are increaseddisproportionately. Furthermore, problems arise with respect tosupplying fluid under pressure, especially in the case of pneumaticcylinders, since a correspondingly high fresh air pressure must be builtup and the air consumption increases. Moreover, the costs ofconstructing suitable single stage cylinders, which can be used with theusual piston pumps for pumping ink, increase.

It is therefore an object of the present invention to provide a devicefor supplying ink to printing presses of the type named above, thedriving force of which device can be increased for increasing the volumepumped and the pumping pressure of which can be increased while avoidingthe structural disadvantages named above.

Pursuant to the invention, this objective is accomplished by a devicefor supplying printing ink with the distinguishing features of claim 1.

The cylinder driving mechanism of the inventive device for supplyingprinting ink comprises several cylinder chambers, which are separatedfrom one another and each of which contains a driving piston, which canbe acted upon with hydraulic or pneumatic pressure. Due to thisconstruction, a higher driving force can be attained without having tobuild up an excessive pre-pressure in the pressure fluid and without anexcessive consumption of fluid. Moreover, the external dimensions ofsuch a cylinder driving mechanism are kept within justifiable limits.

For a preferred embodiment, the cylinder driving mechanism comprises atleast one tandem cylinder.

In a further preferred embodiment, the cylinder driving mechanismcomprises at least two cylinder chambers, which are disposed parallel toand next to one another and which each contain a driving piston.

In the following, a preferred example of the invention is described ingreater detail by means of the attached drawing, in which

FIG. 1 shows a perspective view of an embodiment of the inventive devicesupplying ink to a printing press,

FIG. 2 shows a perpendicular longitudinal section through the cylinderdriving mechanism of the device for supplying ink along the plane A-A inFIG. 1 and

FIG. 3 shows a further longitudinal section in a plane B-B, which isperpendicular to the plane A-A.

The device 10 of FIG. 1 is provided for pumping ink from an ink barrelto an offset printing press. For the sake of clarity, the barrel as wellas a printing press has been omitted in the Figure. As essentialelements, the device 10 for supplying ink comprises a piston pump 12 ina lower section of the device 10 and a pneumatic cylinder drivingmechanism 14, which is mounted thereabove. The piston pump 12 and thecylinder driving mechanism 14 are disposed above one another in the formof a vertical column. As will be explained in even greater detail in thefollowing, the cylinder driving mechanism 14 drives a vertical pistonrod, which extends in the interior of the piston pump 12, linearly in anup and down motion. For this purpose, the piston rod extends upward intothe cylinder driving mechanism 14 and is provided with a driving piston,which can be acted upon with compressed air. Details of the constructionof the driving mechanism 14 will be explained in even greater detail inthe following.

The piston pump 12 itself is of a known construction and comprises acylindrical tubing 18, in which a pumping piston is driven up and downby a piston rod. The lower end of the tubing 18 is connected over aconnector 20, which is provided with seals and seals an inlet pipe 22,at the free and 24 of which a hose or a pipeline for connection with theink barrel can be connected. The inlet pipe 22 is connected by aconnector 20 at right angles with the tubing 18. A foot plate 26 formounting on the floor, on a machine frame or the like, adjoins the lowerend of the connector 20.

The piston pump 12 furthermore comprises two connecting lines 28, 30,which start out laterally from different places of the periphery of thetubing 18 and are to be connected to hoses supplying the printing press,which is not shown. Accordingly, the piston pump 12 pumps the ink,aspirated through the inlet pipe 22 over the connector 20 and the tubing18, through the connecting lines 28, 30 to the printing press.

The pneumatic cylinder driving mechanism 14 comprises a vertical tandemcylinder 32, the interior of which has two separate cylinder chambers,in each of which a driving piston can be moved up and down. Both drivingpistons are mounted at the piston rod of the piston pump 12, the pistonrod extending upward into the tandem cylinder 32. A lower, squareterminating plate 34 and a corresponding upper terminating plate 38close off the tandem cylinder 32 at the upper and lower ends, while anintermediate plate 36, halfway between the two terminating plates 34,38, separates the two cylinder chambers from one another in the interiorof the tandem cylinder 32. An upper casing section 40 and a lower casingsection 42 are disposed in each case between the upper terminating plateand the intermediate plate and between the lower terminating plate 34and the intermediate plate 36 and, in each form the outer limiting wallof a cylinder chamber. Four outer struts 44, the ends of which arebolted to the corners of the plates 34 and 38 and which extend throughthe intermediate plate 36, give the tandem cylinder 32 adequatemechanical stability.

A control unit 46 in a switchbox, which is mounted outside on the sideof the cylinder driving mechanism 14, acts on the driving piston withinthe tandem cylinder 32. The control unit 46 distributes compressed air,which is supplied by a compressed air line 48, over compressed air lines50 to four compressed air connections 52, 54, 56, 58, which are mountedin pairs at the tandem cylinder 32. Each pair of compressed airconnections 52, 54 as well as 56, 58 serves to act with compressed airupon one of the two cylinder chambers of the tandem cylinder 32 in oneof two directions of motion of the driving piston contained therein and,at the same time, to discharge the air, displaced by the driving pistonduring its movement, through rapid air bleeders 60 at the compressed airconnections 52, 54, 56, 58, as explained further below. The upper pairof compressed air connections 52, 54 is mounted one above the other atthe upper terminating plate 38 and at the intermediate plate 36 in FIG.1, front right at the cylinder driving mechanism 14, while the pair oflower compressed air connections 56, 58 is mounted front left at theintermediate plate 36 and the lower terminating plate 34.

The sections in FIGS. 2 and 3 explain the mode of functioning of thetandem cylinder 32. The intermediate plate 36 divides the interior ofthe tandem cylinder 32 into two cylinder chambers of equal size, namelya first cylinder chamber 62 between the lower terminating plate 34 andthe intermediate plate 36 and a second cylinder chamber 64, which isdisposed above in the operating position in FIG. 1 between the middleplate 36 and the upper terminating plate 38. In each of the two cylinderchambers 62, 64, a driving piston 66, 68 is disposed, which closes offthe cylinder chamber 62, 64 air-tight at its periphery with the outersection of the casing 40, 42. If therefore the piston 66, 68 is actedupon with the pressure on one of its sides, it moves in a sliding motionto the opposite side.

An upper section of the piston rod 70 extends from the piston pump 12,which is not shown, through the lower terminating plate 34 and theintermediate plate 36 through the driving piston 66 of the firstcylinder chamber 62 into the driving piston 68 of the second cylinderchamber 64. The piston rod 70 is guided and slides in the lowerterminating plate 34 and in the intermediate plate 36. However, it isseated firmly in the two driving piston 66, 68 and is connected withthese in one piece, so that the piston rod 70 is always carried alongduring a movement of the driving piston 66, 68. Accordingly, by theaction of pressure on the driving piston 66, 68 from above, the pistonrod 70 is pressed into the piston pump 12 and, by the action in theopposite direction, it is pulled out once again.

Compressed air acts on the respective cylinder chamber 62, 64 overcompressed air channels, which are passed into the respectiveterminating plates 34, 38 as well as into the intermediate plate 36. Inparticular, a first, middle compressed air channel 72, which extends inthe radial direction perpendicularly to the piston rod 70 into theintermediate plate 36 and is angled therein to the second cylinderchamber 64, and an also angled upper compressed air channel 72 in theterminating plate 38 serves to act upon the second cylinder chamber 64with compressed air over the first compressed air connection 52 from theopposite side of the driving piston 68.

As is evident in FIG. 3, a second middle compressed air channel 76extends similarly in the intermediate plate 36 to the first cylinderchamber 62 in order to act upon the lower driving piston 66 withcompressed air from above, which is supplied over the compressed airconnection 56 in FIG. 1, while a lower compressed air channel 78 ispassed into the lower connecting plate 34 in the radial direction anddischarges into the opening 80, through which the piston rod 70 ispassed through the lower connecting plate 34. Due to the axial opening80, there is a connection between the lower compressed air channel 78and the first cylinder chamber 62, so that the latter is acted upon withpressure over the lower compressed air connection 58 or, alternatively,if the lower driving mechanism piston 66 is moving in the oppositedirection, can be vented over the rapid air bleeder 60.

During the operation of the driving cylinder, initially the uppercompressed air connections 52, 56 of the respective cylinder chambers62, 64 are acted upon with pressure, so that the pressure is transferredto the respective upper action surfaces of the driving piston 66, 68 andpresses these, together with the piston rod 70, in the direction of thepiston pump 12. Alternatively, the air, displaced by the driving piston66, 68, can escape rapidly over the compressed air channels 72, 78 andthe rapid air bleeder 60 of the compressed air connections 54, 58.Moreover, the driving cylinders 66, 68 move out of the end position,shown in FIGS. 2 and 3, to their lower stop at the intermediate plate 36and the lower terminating plate 34 respectively. Subsequently, thepiston rod 70 is moved in the opposite direction, in that the drivingpistons 66, 68 are acted upon from their underside with pressure by wayof the compressed air channels 72, 78, so that they are pressed upward,while the displaced air on the opposite side of the driving piston 66,68 escapes through the compressed air channels 74, 76. In this way, byalternately acting upon the appropriate pressure connections 52, 54, 56,58 with compressed air, an up and down movement of the driving pistons66, 68 and, with that, of the piston rod 70 can be obtained.

Compared to a one-stage pneumatic cylinder, the tandem cylinder 32,presented here, has the advantage that the driving force, transferred tothe piston rod 70, can be increased without having to increase thepressure or consumption of the air supplied significantly. As can beseen particularly in FIG. 1, the external dimensions of the cylinderdriving mechanism 14 as a whole are maintained within justifiablelimits. By increasing the driving force with relatively simple means,the pumping pressure and the volume pumped by the piston pump 12 can beincreased in a simple manner.

The present invention is not restricted to hydraulic or pneumatic tandemcylinders in the strictest sense. Instead, other arrangements ofseparate cylinder chambers of the driving mechanism are alsoconceivable, such as a multistage driving mechanism with severalconsecutively connected chambers in structurally separate cylinders, thedriving pistons of which are seated on a piston rod 70, extendingthrough the cylinders, in much the same way as shown here in theExample. Moreover, the cylinder chambers of the driving mechanism 14 maybe disposed in parallel and their driving pistons may act jointly on thepiston rod 70.

1. A device for supplying ink to a printing press, comprising: a pistonpump having a piston rod, and a cylinder driving mechanism which drivesthe piston rod of the piston pump, the cylinder driving mechanismincluding several cylinder chambers which are separated from one anotherand each of which includes a driving piston which can be acted upon withpressure.
 2. A device for supplying ink of claim 1, wherein the cylinderdriving mechanism comprises at least one tandem cylinder.
 3. A devicefor supplying ink of claim 1, wherein the cylinder driving mechanismcomprises at least two parallel cylinder chambers, which are disposednext to one another, each of which includes a driving piston.
 4. Adevice for supplying ink of claim 1, wherein said cylinder drivingmechanism is one of: a pneumatic cylinder driving mechanism, and ahydraulic cylinder driving mechanism.
 5. A device for supplying ink ofclaim 2, wherein the cylinder driving mechanism comprises at least twoparallel cylinder chambers, which are disposed next to one another, eachof which includes a driving piston.
 6. A device for supplying ink ofclaim 1, wherein the cylinder driving mechanism comprises at least twoserial arranged cylinder chambers, which are disposed one above another,each of which includes a driving piston.